The present invention relates, generally, to radiosondes and, more particularly, to bobbin apparatus for releasing or paying out a filament which interconnects a radiosonde and a sonde balloon in a controlled manner during the ascent of the sonde balloon.
Information as to atmospheric conditions such as meteorological conditions, is obtained using radiosondes, namely miniature radio transmitters with instruments attached which are carried by unmanned gas-filled balloons to extremely high elevations.
During their ascent, such sonde balloons tend to leave a wake in their path in which the atmospheric conditions vary from the true ambient conditions to be measured. For this reason, it is common practice to suspend the radiosonde from the balloon by a relatively long filament having a length of, for example, about 50 meters. It is possible in this manner to eliminate the influence of the sonde balloon on the atmospheric conditions being measured.
Since it is necessary for the balloon and associated radiosonde to be released in a manner such that they ascend simultaneously, it is known in the art to employ mechanical apparatus affixed beneath the balloon which permits the filament to be released or payed out from a spool or bobbin affixed beneath the balloon at a controlled rate. Such mechanical apparatus may, for example, constitute a mechanically actuated pendulum or a friction brake.
Conventional mechanical apparatus of the type described above are not entirely satisfactory in that the same have a relatively complicated construction to insure reliability in use and are therefore quite expensive. However, since such apparatus are generally discarded after only a single use, it will be appreciated that conventional bobbin apparatus are less than satisfactory from the cost standpoint.